title: The effectiveness of exercise interventions to prevent sports injuries: a systematic review and meta-analysis of randomised controlled trials.
abstract: BACKGROUND
  Physical activity is important in both prevention and treatment of many common diseases, but sports injuries can pose serious problems.
  
  
  OBJECTIVE
  To determine whether physical activity exercises can reduce sports injuries and perform stratified analyses of strength training, stretching, proprioception and combinations of these, and provide separate acute and overuse injury estimates.
  
  
  METHODS
  PubMed, EMBASE, Web of Science and SPORTDiscus were searched and yielded 3462 results. Two independent authors selected relevant randomised, controlled trials and quality assessments were conducted by all authors of this paper using the Cochrane collaboration domain-based quality assessment tool. Twelve studies that neglected to account for clustering effects were adjusted. Quantitative analyses were performed in STATA V.12 and sensitivity analysed by intention-to-treat. Heterogeneity (I(2)) and publication bias (Harbord's small-study effects) were formally tested.
  
  
  RESULTS
  25 trials, including 26 610 participants with 3464 injuries, were analysed. The overall effect estimate on injury prevention was heterogeneous. Stratified exposure analyses proved no beneficial effect for stretching (RR 0.963 (0.846-1.095)), whereas studies with multiple exposures (RR 0.655 (0.520-0.826)), proprioception training (RR 0.550 (0.347-0.869)), and strength training (RR 0.315 (0.207-0.480)) showed a tendency towards increasing effect. Both acute injuries (RR 0.647 (0.502-0.836)) and overuse injuries (RR 0.527 (0.373-0.746)) could be reduced by physical activity programmes. Intention-to-treat sensitivity analyses consistently revealed even more robust effect estimates.
  
  
  CONCLUSIONS
  Despite a few outlying studies, consistently favourable estimates were obtained for all injury prevention measures except for stretching. Strength training reduced sports injuries to less than 1/3 and overuse injuries could be almost halved.
authors.affiliation: Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, , Copenhagen NV, Denmark.
authors.forename: Jeppe Bo
authors.initials: JB
authors.lastname: Lauersen
authors.forename: Ditte Marie
authors.initials: DM
authors.lastname: Bertelsen
authors.forename: Lars Bo
authors.initials: LB
authors.lastname: Andersen
mesh_terms: D000293:Adolescent; D000328:Adult; D001265:Athletic Injuries / Q000517:prevention & control*; D002648:Child; D012090:Cumulative Trauma Disorders / Q000517:prevention & control; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D016032:Randomized Controlled Trials as Topic; D055815:Young Adult
keywords: Evidence based reviews; Injury Prevention; Orthopaedics; Sporting injuries; Training